u-joint issue

I did u joints on my 2003 yukon xl a week ago. Drove it about 300 miles with no issue. I noticed a vibration today around 30 mph. So I jack the truck up, put it in gear and got it up to about 30mph. I did not see anything weird with the drive shaft, and the joints are not warm after a hard 60 mile drive. I had a heck of a time getting one of the clips on the u joint. I tried "springing" the yoke back by hitting it a few times with a hammer. The front joint moved very freely in one direction, but in the direction that I had a had time with the clip it was a little tight. Not real tight, but it did not slap around like the other one. I don't get how for 300 miles it was fine and now I feel a vibration. Any ideas. Thanks

You have aluminum drive shaft so beating on it with a hammer is not a good idea. If the clip is not seated on the groove, it probably popped out. If you lost one, you can use the old one. Use a 10-inch c-clamp and socket to push on the side that lost the clip. This will center the needle bearing cups and allow you to install the clip on the groove.
Also check the drive shaft balancing weights. Put the rear end on jackstands, chock the front wheels, put the transmission in neutral and spin the driveshaft to check the weights.
Good luck.

Just so everyone knows, I did not beat on it! My repair manual says to "strick the yoke sharply with a hammer to spring the ears back", it did loosen one side of the front joint nicely! I figured out what the issue was. Apparently the cheap A$$ u-joint I bought from autozone was not within specs. I crawled under the truck Saturday and had no play in the drive shaft. I drove it to class 40 miles each way. The vibration starting happening at all speeds. So when I got home I crawled under it and I could move the shaft in the rear. The clips between the straps where too close together and I could actually move the joint about 1/16 of an inch each way before the clip bumped into the straps. I bought a new joint and it seems fine now. The front ujoint is still tighter then I would like it to be. So I may take it to the driveshaft place up the street and see what they say. Thanks everyone for the help/

You have aluminum drive shaft so beating on it with a hammer is not a good idea. If the clip is not seated on the groove, it probably popped out. If you lost one, you can use the old one. Use a 10-inch c-clamp and socket to push on the side that lost the clip. This will center the needle bearing cups and allow you to install the clip on the groove.
Also check the drive shaft balancing weights. Put the rear end on jackstands, chock the front wheels, put the transmission in neutral and spin the driveshaft to check the weights.
Good luck.

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I have a steel drive shaft! I did notice that when I replaced the rear one of the caps is actually spinning in the yoke and strap. I am having the yoke replaced today. There is damage from the last joint moving up and down in between the straps so the new joint does not fit tightly. The clips put a groove in the place that they are supposed to rest. Then on monday I am taking the shaft to a shop and having them look at it.

update: So, after noticing the loose u joint in the rear, I replaced it. I was still getting a squeak. My rearend shop looked at it and said that the rear pinion yoke was damaged, I could move the joint around in it. So after I had that replaced, I took the drive shaft to a shop to have the ears of the yoke straightened after my dumb a$$ bent them changing the u joints. I have done 100s of u joints and never had an issue. Not sure if I bent it or they were bent by the last guy that did them. The family does long road trips at night so I did not want to get stuck on route 2 at 2 am. They wanted to cut them off and replace the yokes to the tune of $390. I brought it home, took it apart and beat on them to try to straighten them out. It got a little better but not much, so I found a reman drive shaft at napa for $290. I went to put it in and noticed that one of the straps for the rear pinion yoke had a crack all the way through it. (they did not replace them when they replace the yoke) So, i now have a new drive shaft, u joints, pinion yoke and straps. Have driven it for about 100 miles with out an issue. Hopefully I am done with the rear end of this thing for a couple years.